DBA_FREE_SPACE视图记录了数据库中所有表空间的自由extents情况，所以可以从该视图获得各表空间自由空间情况。
SQL> desc dba_free_space
Name Null? Type
----------------------- ------------- -----------------
TABLESPACE_NAME VARCHAR2(30)
FILE_ID NUMBER
BLOCK_ID NUMBER
BYTES NUMBER
BLOCKS NUMBER
RELATIVE_FNO NUMBER
可以使用如下SQL进行查询:
select tablespace_name,sum(bytes)/1024/1024 free_Mbytes
from dba_free_space
group by tablespace_name
order by free_Mbytes
/
示例输出:
SQL> select tablespace_name,sum(bytes)/1024/1024 free_Mbytes
2 from dba_free_space
3 group by tablespace_name
4 order by free_Mbytes
5 /
TABLESPACE_NAME FREE_MBYTES
-------------------- -----------
USERS .75
UNDOTBS1 18.6875
SYSTEM 42.6875
